How does a PET scan work? | Nuclear medicine

[Music] hi everyone my name is pauline i'm a belgian nuclear medicine resident and this video is an introduction to pet imaging first i will tell you the differences between pet ct x-ray and mri then i will tell you how pet scans are used to detect cancer and finally i will tell you if radiation from a pet scan is dangerous pet ct x-ray and mri are commonly used imaging techniques ct x-ray and mri belong to radiology and pad belongs to the field of nuclear medicine the main difference between those two groups is their focus ct x-ray

and mri create detailed images of organs bones and other tissues a pet scan on the other hand shows doctors how the tissues in your body work on a molecular level ct x-rays and mri are therefore called structural imaging techniques whereas pet is a functional imaging technique for example if you have pain in your ankle and the doctor suspects a fracture you will order an x-ray or a ct scan both imaging techniques are good at diagnosing bone injuries if it will be most likely a ligament injury the doctor will order an mri scan this is because

mri is better suited for examining soft tissue injuries particularly in the ligaments or tendons and finally if a bone tumor is suspected a bad scan will be performed pet uses a radioactive drug called a tracer to look at the function of your organs the most commonly used pet tracer is a molecule called fdg fdg is nothing more than a glucose or a sugar molecule with a radioactive part attached to it in a little under two hours about half of the radioactivity will be gone due to radioactive decay so the clock is sticking to get the

scan done because fdg is very similar to glucose our body uses it like it uses glucose fdg travels through your body and gathers in cells that are using a lot of energy such as cancer cells the radioactive material decays and gives off tiny positively charged particles which we call positrons a camera will record the positrons and will turn the recording into pictures on a computer cancer cells show up as bright spots on a pet scan because they use more glucose than normal cells in this way a pet scan can help to show cancer find out

how big it is and whether it has spread to other parts of your body one of the most important features of a pet scan is that it allows physicians to see changes in the tumor before they are visible in other images changes in glucose used by a tumor happen before the size changes and images from traditional ct and x-rays only show the size and the shape of the tumor so many cancers can be detected using bed before they can be seen using other imaging techniques is a pet scan safe even though no amount of ionizing

radiation is completely safe the amount of radiation the body receives during a pet scan is actually quite low one scan is comparable to what you're exposed to over two or three years from natural radioactive sources or the amount of cosmic radiation a pilot would be exposed to after 25 long distance flights in general a pet scan is considered to be a safe procedure and the benefits of having a pet scan outweigh the risk of exposure to the small amount of radiation received during the scan so remember that that visualizes how well your organs and tissues

are functioning whereas x-ray ct or mri give you anatomical detail of the structures and tissues of your body furthermore that uses glucose-specific traces such as fdg to diagnose cancer this is because cancerous cells take up more glucose than the rest of our cells and finally pet scans do carry a risk of radiation but the benefits of these tests are usually greater than the risks thank you so much for watching this video if you liked the video please give it a thumbs up it would really help me you